Gradometer



Jan. 10, 1950 G, CRAFT ET AL 2,493,946

GRADOMETER Filed Dec. 18, 1947 IN V EN TORS V6. Car/son Glen CraftPatented Jan. 10, 195( OFFICE GE BOMEFBE 1 n waters (lulfignnQherpkee, 1

-m be 1 47,. 'Serial'No;792;564 @Ql ims- (01. 33

This invention melates to improvements in gradometers, and has for itsprincipal object the provision of a device adapted for attachment ito avehicle such as a tractor in view of the driver to provide a guide dormaintaining :contour lines in farming operations.

A general object of the invention is to provide a device whichwillenable a farmer to determine the slope of a field and make anynecessary contour adjustment :as he gplpws whereby to avoid the tediousand time consuming, method heretofore employed of walking over the fieldwith .a hand level and staking out contour lines preparatory tosubsequent plowing.

A further and more specific object of the inventionis to provide agradometer of ruggedzanii durable construction .to withstand usage on afarm tractor .but capable of constantly accurate slope measurement.during :and after #long pcriods .of such usage.

Another object is to proyide a gradometer pendulum and indicatorconstruction having the parts thereof shielded against breakage ordamagefrom contact with .other objects and ,protected against injury andmaladjustment which might ordinarily result from extremes of abruptmovement.

Other and further objects and advantages of the invention will beapparent from the "following detailed description taken in conjunctionwith the accompanying drawings wherein a preferred embodiment of theprinciples of the invention has been selected for exemplification.

In the drawings:

Fig. 1 is a front elevational view of a gradometer constructed inaccordance with the invention; I

Fig. 2 is a central vertical sectional view of the device shown in Fig.1;

Fig. 3 is a vertical sectional view taken on the line 3-3 of Fig. 2; and

Fig. 4 is a perspective view looking downwardly at the rear of thedevice with the cover removed to show the pendulum support and camconstruction.

Referring more particularly to the drawings,

wherein like numerals refer to like parts, a housing is provided havingside walls In and a bottom wall l2 which preferably is arcuatesubstantially to parallel the path of the swinging pendulum bob, asshown. The housing is adapted to contain a body of fluid, for example,an oil of uniform viscosity at various extremes of temperature, to dampand cushion the movement of the pendulum. A cover [4 prevents spillageof the ,2 fluid and protects the operating parts positioned within thehousing.

A gravity a-pendulum :bob 1:6 is secured to the lower .portion .of )3rigid arm [8, the longitudinal edges of which .are -laterally .bent andapertured at their upper portion .to receive a horizontal shaft 20 whichis fixed transverselylof the housing to provide a pivotal support forthe pendulum. To prevent arm l8 from sliding axially of the shaft 2 0:collars 52z| are :disposed between :the bent edges :of the arm and:adjacent side walls of the housing.

The farm 21.6 is relatively wide, extending a :sub stantialapart of thewidth of the 1housing, as that its etc :and fro .swing will be resistedto .a certain degree by the liquid within the housing. Such resistancemay be controlled and the weight of arm 1:8 decreased by the provisionof apertures, ashhewnxinf'igfi. Further to restrict the swing ofathependulum arm i8 and functioning also to reduce friction :by relievingthe weight of the pendulum ion journal shaft .26, a tension spring 22 isinterposed between the upper end of arm l8 and the adjacent wall portion24 of the housing.

a The wall portion .24, as .shown, is flared and adaiits upper .edgecalibrations graduating outwardly medially :of its :ends. Verticallypositioned pointer 26 is adapted to register with such calibrations andis protected by a guard plate 28 offset outwardly of and carried by thewall 24.

The laterally bent lower end of pointer 26 projects through the adjacentwall of the housing and is secured to a collar 39. Adjustably fixed incollar 30 by means of a set screw 32 is one end of a shaft 34, the otherend of which is journalled in a bracket 36 carried by the housing wall.Shaft 34 extends axially of the laterally bent end of pointer 26 towhich it is secured and as the shaft 34 tends to rotate the pointer 26will be moved in a corresponding direction, the extent of such movementbeing registered on the calibrated dial. To translate forward andrearward tilting of the housing on a horizontal axis to movement of thepointer 26 in an upright plane, a cam 38, which may conveniently becarried by an ear 4!] struck of the pendulum arm I 8, engages anelongated cam follower 42 fixed to the shaft 34. Thus, forward tiltingof the housing, as when the vehicle to which it is attached facesdownhill Will elevate cam 38 and, as the cam rides in the cam follower42, the shaft 34 will tend to rotate in a counterclockwise direction andmove pointer 26 along the down side of the calibrated dial. Conversely,rearward tilting of the housing as when the vehicle faces uphill,

3 will lower cam 38 and, as the cam rides in cam follower 42, the shaft34 will tend to rotate in a clockwise direction and move the pointer 26along the up side of the dial. The extent of the grade will, of course,be registered on the dial for the guidance of the vehicle operator.

In operation, as in contour plowing, the device above described ismounted upon the dashboard or steering column or engine hood of atractor or other vehicle in a manner to be readily visible to theoperator and the pointer 26 is set at the level or zero point of thedial by adjusting the relative positions of the shaft 34 and collar 39-by means of the set screw 32. As the tractor proceeds, the device willreflect the percent of slope above or below the level or contour line sothat the operator may readily correct the position of the plow wheneverthe pointer moves from 2. A gradometer comprising, an upright housingsupporting a calibrated dial at its upper portion and having a lowerportion adopted to contain a body of damping fluid, a pendulum armcarrying a pendulum bob disposed in said body of damping fluid, saidpendulum arm being of paddle-like form whereby to present a relativelybroad surface area to the damping fluid in the direction of its path ofmovement, a shaft extending transversely of saidhousing on a fixed axisto provide a bearing support for said pendulum arm, means for supportingsaid pendulum arm intermediate its height on said shaft, spring meansdepending from the upper portion of said housing and connected to theupper end of that portion of said pendulum arm which extends above saidshaft to. relieve the bearing weight of the zero point. Thus, a fieldmay be surveyed as it is plowed and the tedious system heretofore used.of walking out contour lines to guide the tractor may be avoided.

It will be understood that the device herein described and illustratedis exemplary only of the principles of the invention which embrace suchmodified structures as come within the scope of the following claims.

Having described our invention what we claim is: V

1. A gradometer comprising, an upright housing, a shaft extendingtransversely of an intermediate portion of said housing on a fixed axisto provide a bearing support, a pendulum .arm including a pendulum bobdisposed within said housing and supported bysaid shaft, the saidpendulum arm carrying apertures below its upper extremity to receivesaid shaft and the upper ex-. tremity of said pendulum arm extendingabove said shaft, spring means depending from the upper portion of saidhousing and connected to the upper extremity of said pendulum arm tostabilize and to relieve the bearing weight of said pendulum arm and bobupon said shaft, a calibrated dial carried by the upper portion of saidhousing and having an operatively associated indicating .46

pointer and means for transmitting the motion of said pendulum arm tosaid indicating pointer.

said pendulum arm and bob upon said shaft, an indicating pointeroperatively associated with said dial and means for transmitting themotion of said pendulum arm to said indicating pointer.

3. Thedevice of claim 2 wherein, the pendulum arm supporting meanscomprises, laterally bent portions provided on'opposed longitudinalsides of the pendulum arm, each of said portions being apertured toreceive the supporting shaft.

' GLEN CRAFI.

VICTOR G. CARLSON.

REFERENCES CITED ,The following references are of record in the file ofthis patent:

UNITED STATES PATENTS

